1. Field of the Invention
This invention relates to a process for the production of bonded hard alloys and more particularly, it is concerned with a process for bonding one or more kind of hard alloys using a high energy beam.
2. Description of the Prior Art
Bonding of a plurality of tool parts of hard alloys such as cemented carbides to obtain a tool formed in one body would result in various merits such as making it possible to obtain an article with a complicated shape or with such a large size as to exceed the limit reached by cemented carbides. It would also be possible to combine two or more kinds of hard alloys having different properties. However, since the melting point of the hard alloy is so high that a high temperature, e.g. 1320.degree. C. or higher is required for forming a liquid phase of the alloy, there is no way to accomplish this except by effecting diffusion bonding in a furnace under pressure.
Therefore, the most economical bonding method comprises using a silver braze or copper braze, but the bonding using such a braze is poor, in particular, when wetting of the braze is inferior. Furthermore, even if the bonding is completed, a shearing strength only about 10 to 20 kg/mm.sup.2 is expected.
When cemented carbides are used as a structural part or as a wear resisting tool such as a die, slitter and bit, a higher shearing force, fatigue strength and impulsive force are required.
Thus, it has eagerly been desired to develop a bonding method whereby cemented carbides can be bonded easily and completely independently of their shapes or sizes.